Frac Growth Diagnostic Analysis Using Fiber and Sealed Well Integrated Data

Abstract

Abstract A trial was executed in unconventional field of Saudi Aramco to characterize the hydraulic frac growth for two different state of the art frac designs by monitoring acoustic and pressure responses in offset wells using fiber optics & sealed wellbore pressure data, respectively. Hydraulic frac characterization helped in evaluating the frac designs, cluster efficiency, parent-child interaction, and frac-hits which will help in the selection of the frac design for the development phase. Two north wells of a single pad were fractured with design-A (less intense design), while two south wells of the same pad were fractured with design-B (highly intense with engineering limited entry). These north and south wells were monitored through their offset wells in different pads by deploying fiber and pressure gauges in the sealed wellbores. Fiber helped identifying fracture corridors, previous stage reactivation, frac-hit time and intensity, and volume to first response (VFR). While sealed well pressure data helped identifying frac-hit time and intensity, and volume to first response (VFR). volume to first response (VFR) at the monitor well is an inversely proportional indicator of frac half length. Fracture corridor from fiber data at monitor well was used to estimate the frac corridor widths for all the stages in addition to the magnitude of pressure/strain changes observed due to frac-hits to estimate the intensity of frac-hits. Combining fiber with a sealed wellbore helped in establishing the baseline for sealed wellbore pressure observation and its interpretation for future wells. Data from both sources was captured successfully. Frac-hits identified by fiber were further endorsed by sealed wellbore pressure data along with the frac-hit time, with an excellent correlation of R2-0.93. Results of this trial showed two distinct responses for two different designs (design-A and design-B). High volume to first response (VFR) in design-A compared to design-B initially suggested a more heterogeneous fracture network being created in design-A. However, frac corridors from fiber data showed that the majority of design-A frac corridors were reactivating previous stages and resulting in high VFRs. On the other hand, design-B had a more effective fracture corridor with significantly less overlap to the previous stages, resulting in low VFRs. Moreover, frac-hits were more intense and contained in design-B compared to design-A. This paper will present the impact of these two different designs on production. Lessons learned, interpretation best practices for both fiber and sealed-wellbore monitoring pressure, and the correlation among major KPIs (being estimated from the acquired data) will be presented in this article for cases where both technologies were run into a single wellbore. This helped better characterize the fracture growth and will help in future job planning and interpretation of the data for frac characterization.